Monoazo compounds

ABSTRACT

A monoazo compound of the Formula (1) and salts thereof: ##STR1## wherein each of R 1  and R 2 , independently, represents H, halogen, alkyl, alkoxy or acylamino; each of R 3 , R 4  and R 5 , independently, represents H or optionally substituted hydrocarbyl other than groups comprising the residue --A&#39;NR 7  R 8  wherein A represents an optionally substituted alkylene group containing 2 or more carbon atoms and each of R 7  and R 8 , independently, represents H or optionally substituted hydrocarbyl or R 7  and R 8  together with the attached nitrogen atom form a 5- or 6-membered ring and R 6  represents an optionally substituted hydrocarbyl group not comprising the residue --A--NR 7  R 8  wherein A, R 7  and R 8  are as defined above; or R 3  and R 4  together with the attached nitrogen atom and/or R 5  and R 6  together with the attached nitrogen atom form a 5- or 6-membered ring other than a piperazine ring, the compounds of Formula (1) being free from fibre-reactive groups and any carboxyl substituents present in the compounds being attached in the form of one or more residue of the following formulae: ##STR2## also claimed are ink compositions comprising the above compound; a process for printing substrates with the ink compositions using an ink-jet printer; paper, project slides and textile materials printed with the ink compositions; and a process for coloration of textile materials with the ink compositions.

This is a continuation of application Ser. No. 08/768,959, filed on Dec.18, 1996 , which was abandoned upon the filing hereof.

This invention relates to chemical compounds and more particularly tocoloured monoazo compounds to ink compositions and solutions thereof,and to processes for use in printing and imaging technologies,especially those suitable for coloration of substrates including paper,plastics, textiles, metal and glass such as inkjet printing.

Inkjet printing is a non-impact printing technique which involvesejecting, thermally or by action of an oscillating piezo crystal,droplets of ink continuously or on demand from a fine nozzle directlyonto a substrate such as paper, plastics, textile, metal or glass. Theink may be aqueous, solvent or hot melt based and must provide sharp,non-feathered images which have good waterfastness, light fastness andoptical density, have fast fixation to the substrate and cause noclogging of the nozzle.

According to a first aspect of the present invention, there are providedmonoazo compounds of the Formula (1) and salts thereof: ##STR3## whereineach of R¹ and R², independently, represents H, halogen, alkyl, alkoxyor acylamino; each of R³, R⁴ and R⁵, independently, represents H oroptionally substituted hydrocarbyl other than groups comprising theresidue --A--NR⁷ R⁸ wherein A represents an optionally substitutedalkylene group containing 2 or more carbon atoms and each of R⁷ and R⁸,independently, represents H or optionally substituted hydrocarbyl or R⁷and R⁸ together with the attached nitrogen atom form a 5- or 6-memberedring and R⁶ represents an optionally substituted hydrocarbyl group notcomprising the residue --A--NR⁷ R⁸ wherein A, R⁷ and R⁸ are as definedabove; or R³ and R⁴ together with the attached nitrogen atom and/or R⁵and R⁶ together with the attached nitrogen atom form a 5- or 6-memberedring other than a piperazine ring, the compounds of Formula (1) beingfree from fibre-reactive groups and any carboxyl substituents present inthe compounds being attached in the form of one or more residue of thefollowing formulae: ##STR4##

Halogen substituents which may be represented by R¹ and R² in thecompounds of Formula 1 particularly include chloro substituents. Alkyl,alkoxy and acylamino substituents which may be represented by R¹ and R²particularly include C₁₋₆ -alkyl groups, for example methyl, C₁₋₆-alkoxy groups; for example methoxy and C₁₋₆ -acylamino groups, forexample acetylamino.

Optionally substituted hydrocarbyl groups which may be represented byR³, R⁴, R⁵ and R⁶ include alkyl, substituted alkyl, alkenyl, substitutedalkenyl, aryl and substituted aryl especially C₁₋₆ -alkyl, substitutedC₁₋₆ -alkyl, C₃₋₄ -alkenyl, phenyl and substituted phenyl. Any optionalsubstituents on R³, R⁴, R⁵ and R⁶ are preferably independently selectedfrom --OH and --SO₃ H. When R³ and R⁴ together with the attachednitrogen atom and/or R⁵ and R⁶ together with the attached nitrogen atomform a 5- or 6-membered ring, they preferably form a morpholine orpiperidine ring.

As indicated above, R³, R⁴, R⁵ and R⁶ must not be or contain groups ofthe formula --A--NR⁷ R⁸ as defined. Thus, R³, R⁴, R⁵ and R⁶ must not beor contain groups such as aminoethyl or 3-dimethylaminopropyl.

As also stated above, the compounds of Formula 1 are free fromfibre-reactive groups. Such groups have been fully described in theprior art, for example in our EP-A-0356014.

The compounds of Formula (1) may be in the free acid form as shown butare preferably in the form of water-soluble salts, especially alkalimetal, ammonium or substituted ammonium salts.

The compounds of Formula (1) may be prepared by methods analogous tothose described in the prior art for similar monoazo compounds. Thus,for example, a suitable method comprises:

(i) diazotising an aromatic amine of the formula: ##STR5## to form thecorresponding diazonium salt;

(ii) condensing 8-amino-1-naphthol-3,6-disulphonic acid (H acid) withcyanuric chloride, preferably in the presence of a base, to form8-(4,6-dichlorotriazin-2-ylamino)-1-naphthol-3,6-disulphonic acid;

(iii) coupling the diazonium salt with the dichlorotriazinylaminocompound to form a monoazo compound of the formula: ##STR6##

(iv) condensing the monoazo compound of Formula (3) with one molarproportion of a compound of formula R³ R⁴ NH, and

(v) condensing the monoazo product from (iv) with one molar proportionof a compound of formula R⁵ R⁶ NH, preferably in the presence of a base;

wherein R¹, R², R³, R⁴, R⁵ and R⁶ are as defined above, the reactantsbeing selected so that the final product is free from fibre-reactivegroups and also so that any carboxyl substituents present in the productare in the form of one or more residue of the following formulae:##STR7##

As examples of amines of Formula (2) which may be used in thepreparation of compounds of Formula (1), there may be mentionedorthanilic acid, 2-amino-5-methylbenzenesulphonic acid,2-amino-5-methoxybenzenesulphonic acid,2-amino-5-acetylaminobenzenesulphonic acid and2-amino-4,5-dimethylbenzenesulphonic acid.

As examples of compounds of formula R³ R⁴ NH and formula R⁵ R⁶ NH, whichmay be the same or different, there may be mentioned ammonia and primaryand secondary aliphatic and aromatic amines and heterocyclic bases suchas morpholine provided not both are ammonia. Specific amines include4-aminosalicylic acid, 2-amino-5-sulphobenzoic acid,2-amino-5-methylbenzenesulphonic acid and ethanolamine.

The reactions leading to the formation of the compounds of the inventionmay be performed using conditions that have been fully described in theprior art for such reactions. Similarly, the compounds may be isolatedby known methods, for example spray drying or precipitation andfiltration.

According to a further feature of the present invention there isprovided an ink composition comprising a monoazo compound of Formula (1)or salts thereof and a medium.

A compound of the present invention is a useful colorant for an ink, andexhibits high solubility in water and aqueous media and good waterfastness and gives a print with a strong magenta shade on plain paper.The present ink composition may comprise a mixture of two or moredifferent compounds of Formula (1) or salts thereof or may comprise amixture of one or more compounds of Formula (1) or salts thereof withone or more other compounds such as other azo compounds. The compoundsare versatile, exhibiting high water fastness and rapid fixation onalkaline, neutral and acid papers and good solubility in aqueous inkmedia.

A suitable ink composition comprises a compound according to the presentinvention and a liquid medium, preferably an aqueous medium. It ispreferred that the compound is completely dissolved in the liquid mediumto form a solution.

The ink composition preferably contains from 0.5% to 20%, morepreferably from 0.5% to 15%, and especially from 1% to 3%, by weight ofthe compound based on the total weight of the ink. Although many inkscontain less than 5% by weight of colorant, it is desirable that thecompound has a water solubility of around 10% or more to allow thepreparation of concentrates from which more dilute inks can be preparedand to minimise the chance of precipitation of colorant if evaporationof solvent occurs during use of the ink.

The liquid medium is preferably water or a mixture of water and one ormore water-soluble organic solvent. The weight ratio of water to organicsolvent(s) is preferably from 99:1 to 1:99, more preferably from 95:1 to50:50 and especially from 90:10 to 60:40.

The water-soluble organic solvent is preferably selected from C₁₋₄-alkanols such as methanol, ethanol, n-propanol, isopropanol, n-butanol,sec-butanol, tert-butanol, isobutanol or n-pentanol; amides such asdimethylformamide or dimethylacetamide; ketones or ketone-alcohols suchas acetone or diacetone alcohol; ethers such as tetrahydrofuran ordioxane; oligo- or poly-alkyleneglycols such as diethylene glycol,triethylene glycol, hexylene glycol, polyethylene glycol orpolypropylene glycol; alkyleneglycols or thioglycols containing a C₂ -C₆-alkylene group such as ethylene glycol, propylene glycol, butyleneglycol, pentylene glycol or hexylene glycol and thiodiglycol; polyolssuch as glycerol or 1,2,6-hexanetriol; C₁₋₄ -alkyl-ethers or polyhydricalcohols such as 2-methoxyethanol, 2-(2-methoxyethoxy)ethanol,2-(2-ethoxyethoxy)-ethanol, 2- 2-(2-methoxyethoxy)ethoxy!ethanol, 2- 2-(2-ethoxyethoxy) - ethoxy!-ethanol, ethylene glycol monoallyl ether;heterocyclic ketones, such as 2-pyrrolidone and N-methyl-2-pyrrolidone,N-ethyl-2-pyrrolidone and 1,3-dimethylimidazolone and sulphoxides suchas dimethylsulphoxide and sulpholane; or mixtures containing two or moreof the aforementioned water-soluble organic solvents, for examplethiodiglycol and a second glycol or diethylene glycol and 2-pyrrolidone.

Preferred water-soluble organic solvents are 2-pyrrolidone;N-methylpyrrolidone; alkylene glycols and oligo-alkylene glycols, suchas ethylene glycol, diethylene glycol, triethylene glycol; and loweralkyl ethers of polyhydric alcohols such as2-methoxy-2-ethoxy-2-ethoxy-ethanol; and polyethylene glycols with amolecular weight of up to 500. A preferred specific solvent mixture is abinary or ternary mixture of water and diethylene glycol and/or,2-pyrrolidone or N-methylpyrrolidone in weight ratios 75-95:25-5 and60-80:0-20:0-20 respectively.

Examples of suitable ink media are given in U.S. Pat. No. 4,963,189,U.S. Pat. No. 4,703,113, U.S. Pat. No. 4,626,284 and EP-A-0425150.

A further aspect of the present invention provides a process forprinting a substrate with an ink composition using an ink jet printer,characterised in that the ink contains at least one compound accordingto the first aspect of the present invention.

A suitable process for the application of an ink as hereinbefore definedcomprises forming the ink into small droplets by ejection from areservoir through a small orifice so that the droplets of ink aredirected at a substrate. This process is commonly referred to as ink jetprinting, and preferred ink jet printing processes for the present inksare piezoelectric ink jet printing and thermal ink jet printing. Inthermal ink jet printing, programmed pulses of heat are applied to theink in the reservoir by means of a resistor adjacent to the orifice,during relative movement between the substrate and the reservoir.

The substrate used in the inkjet printing process may be paper,plastics, textile, metal or glass and is preferably paper, plastic or atextile material, especially a natural, semi-synthetic or syntheticmaterial.

Examples of natural textile materials include wool, silk, hair andcellulosic materials, particularly cotton, jute, hemp, flax and linen.

Examples of synthetic and semi-synthetic materials include polyamides,polyesters, polyacrylonitriles and polyurethanes.

Preferred substrates include overhead projector slides or papers,including plain and treated papers, which may have an acid, alkaline orneutral character or textile materials such as cotton. An especiallypreferred substrate is paper.

The preferred ink used in the process is as hereinbefore described.

According to a further aspect of the present invention there is provideda paper or an overhead projector slide or textile material printed withan ink composition characterised in that the ink composition comprisesat least one compound of Formula (1) or salt thereof.

According to a further aspect of the present invention there is provideda process for the coloration of a textile material with any of theabovementioned ink compositions which comprises the steps:

i) applying to the textile material by inkjet printing the inkcomposition; and

ii) heating the textile material at a temperature from 50° C. to 250° C.to fix the compound on the material.

The process for coloration of a textile material by inkjet printingpreferably comprises a pre-treatment of the textile material with anaqueous pre-treatment composition comprising a water-soluble base, ahydrotropic agent and a thickening agent followed by removing water fromthe pre-treated textile material to give a dry pre-treated textilematerial which is subjected to inkjet printing in step i) above.

The pre-treatment composition preferably comprises a solution of thebase and the hydrotropic agent in water containing the thickening agent.

The base is preferably an inorganic alkaline base, especially a salt ofan alkali metal with a weak acid such as an alkali metal carbonate,bicarbonate or silicate or an alkali metal hydroxide. The amount of basemay be varied within wide limits provided sufficient base is retained onthe textile material after pre-treatment to promote the dyeing of thepre-treated textile material. Where the base is sodium bicarbonate it isconvenient to use a concentration of from 1% to 5% by weight based onthe total weight of the composition.

The hydrotropic agent is present to provide sufficient water to promotethe fixation reaction between the compound and the textile materialduring the heat treatment, in step (d) above, and any suitablehydrotropic agent may be employed. Preferred hydrotropic agents areurea, thiourea and dicyandiamide. The amount of hydrotropic agentdepends to some extent on the type of heat treatment. If steam is usedfor the heat treatment generally less hydrotropic agent is required thanif the heat treatment is dry, because the steam provides a humidenvironment. The amount of hydrotropic agent required is generally from2.5% to 50% by weight of the total composition with from 2.5% to 10%being more suitable for a steam heat treatment and from 20% to 40% beingmore suitable for a dry heat treatment.

The thickening agent may be any thickening agent suitable for use in thepreparation of print pastes for the conventional printing of cellulosereactive compounds. Suitable thickening agents include alginates,especially sodium alginate, xantham gums, monogalactam thickeners andcellulosic thickeners. The amount of the thickening agent can varywithin wide limits depending on the relationship between concentrationand viscosity. However, sufficient agent is preferred to give aviscosity from 10 to 1000 mPa.s, preferably from 10 to 100 mPa.s,(measured on a Brookfield RVF Viscometer). For an alginate thickenerthis range can be provided by using from 10% to 20% by weight based onthe total weight of the pre-treatment composition.

The remainder of the pre-treatment composition is preferably water, butother ingredients may be added to aid fixation of the compound to thetextile material or to enhance the clarity of print by inhibiting thediffusion (migration) of compound from coloured areas to non-colouredareas before fixation.

Examples of fixation enhancing agents are cationic polymers, such as a50% aqueous solution of a dicyanamide/phenol formaldehyde/ammoniumchloride condensate e.g. MATEXIL FC-PN (available from ICI), which havea strong affinity for the textile material and the compound and thusincrease the fixation of the compound on the textile material.

Examples of anti-migration agents are low molecular weight acrylicresins, e.g. polyacrylates, such as poly(acrylic acid) and poly(vinylacrylate).

In the pre-treatment stage of the present process the pre-treatmentcomposition is preferably evenly applied to the textile material. Wherea deeply penetrated print or a deep shade is required the pre-treatmentcomposition is preferably applied by a padding or similar process sothat it is evenly distributed throughout the material. However, whereonly a superficial print is required the pre-treatment composition canbe applied to the surface of the textile material by a printingprocedure, such as screen or roller printing, ink jet printing or barapplication.

In the pre-treatment stage of the present process, water may be removedfrom the pre-treated textile material by any suitable drying proceduresuch as by exposure to hot air or direct heating, e.g. by infra-redradiation, or micro-wave radiation, preferably so that the temperatureof the material does not exceed 100° C.

The application of the ink composition to the textile material, stage(i) of the present process, may be effected by any ink let printingtechnique, whether drop on demand (DOD) or continuous flow. The inkcomposition, preferably also contains a humectant to inhibit evaporationof water and a preservative to inhibit the growth of fungi, bacteriaand/or algae in the solution. Examples of suitable humectants are,propan-1,2-diol, butan-1,2-diol, butan-2,3-diol and butan-1,3-diol.However, the presence of small amounts, up to about 10%, preferably notmore than 5%, in total, of polyols having two or more primary hydroxyand/or primary alcohols is acceptable, although the composition ispreferably free from such compounds. Where the ink jet printingtechnique involves the charging and electrically-controlled deflectionof drops the composition preferably also contains a conducting materialsuch as an ionised salt to enhance and stabilise the charge applied tothe drops. Suitable salts for this purpose are alkali metal salts ofmineral acids.

After application of the ink composition, it is generally desirable toremove water from the printed textile material at relatively lowtemperatures (<100° C.) prior to the heat applied to fix the compound onthe textile material as this has been found to minimise the diffusion ofthe compound from printed to non-printed regions. As with thepre-treated textile material removal of water is preferably by heat,such as by exposure to hot air or to infra-red or micro-wave radiation.

In stage (ii) of the present process, the printed textile material issubmitted to a short heat treatment, preferably after removal of waterby low-temperature drying, at a temperature from 100° C. to 200° C. byexposure to dry or steam heat for a period of up to 20 minutes. If asteam (wet) heat treatment is used, the printed material is preferablymaintained at 100°-105° C. for from 5 to 15 minutes whereas if a dryheat treatment is employed the printed material is preferably maintainedat 140°-160° C. for from 2 to 8 minutes.

After allowing the textile material to cool, unfixed compound and otheringredients of the pre-treatment and compound compositions may beremoved from the textile material by a washing sequence, involving aseries of hot and cold washes in water and aqueous detergent solutionsbefore the textile material is dried.

According to further aspects of the present invention there are providedtextile materials, especially cellulosic textile materials, colouredwith any of the ink compositions according to the present invention orby means of the process according to the present invention.

The invention is further illustrated but not limited by the followingexamples.

EXAMPLE 1

2-Amino-5-methylbenzenesulphonic acid (9.4 g) was dissolved in water(200 cm³) and the pH was adjusted to 7 by the addition of 2N sodiumhydroxide solution. Sodium nitrite (3.8 g) was added and the wholesolution was added to a mixture of ice/water/concentrated HCl (25 cm³)at 0°-5° C.

1-Amino-8-naphthol-3,6-disulphonic acid (20.0 g) was dissolved in water(400 cm³) and the pH was adjusted to 6 by the addition of 2N sodiumhydroxide solution.

Cyanuric chloride (10.0 g) was added to acetone/ice/water at 0°-5° C.and the H acid solution was added to this over 5 mins at 0°-5° C. Afterstirring for 2 hours, the solution was filtered and then added to thediazo solution prepared as described above.

The pH of the coupling reaction was adjusted to 7 over 1 hr by theaddition of 2N sodium hydroxide solution. Stirring was continued for afurther 2 hours at pH 7 and the total volume was adjusted to 1200 cm³.

To 600 cm³ of the above prepared solution of dichlorotriazinyl monoazocompound was added 4-aminosalicylic acid (3.8 g) and stirring wasmaintained overnight at pH 6-7. The monochlorotriazinyl azo compound soformed was salted out by the addition of 20% sodium chloride solution,filtered off, washed with brine (500 cm³) and dried in a vacuum oven.

The monochlorotriazinylazo compound (8.3 g) was dissolved in water,ethanolamine (1.8 g) was added and the reaction mixture was heated to70°-75° C. for 3 hours. After cooling and dialysis, the product wasdried at 70° C. overnight.

When dissolved in an aqueous ink medium and printed on to plain paperusing a thermal ink jet printing machine, the product gave brightmagenta shades having good water fastness and good light fastness.

The following table gives further examples of monoazo compounds of theformula ##STR8## which were prepared by coupling a diazotised aromaticamine ANH₂ with dichlorotriazinyl H acid and then reacting thedichlorotriazinyl monoazo compound first with a compound of the formulaHNR³ R⁴ and second with a compound of the formula HNR⁵ R⁶.

    ______________________________________                                        Example                                                                              ANH.sub.2      HNR.sup.3 R.sup.4                                                                         HNR.sup.5 R.sup.6                           ______________________________________                                        2      2-amino-5-methyl                                                                             2-amino-5-sulpho                                                                          ammonia                                            benzene sulphonic acid                                                                       benzoic acid                                            3      orthanilic acid                                                                              4-amino salicylic                                                                         ethanolamine                                                      acid                                                    4      2-amino-4,5-dimethyl                                                                         2-amino-5-sulpho                                                                          ethanolamine                                       benzene sulphonic acid                                                                       benzoic acid                                            5      2-amino-4,5-dimethyl                                                                         4-amino salicylic                                                                         ethanolamine                                       benzene sulphonic acid                                                                       acid                                                    6      2-amino-4,5-dimethyl                                                                         ethanolamine                                                                              ethanolamine                                       benzene sulphonic acid                                                 7      2-amino-4,5-dimethyl                                                                         4-aminosalicylic                                                                          2-aminomethyl                                      benzene sulphonic acid                                                                       acid        tetrahydrofuran                             8      2-amino-4,5-dimethyl                                                                         4-aminosalicylic                                                                          ammonia                                            benzene sulphonic acid                                                                       acid                                                    9      2-amino-5-methoxy                                                                            4-aminosalicylic                                                                          ethanolamine                                       benzene sulphonic acid                                                                       acid                                                    10     2-amino-5-methoxy                                                                            2-amino-5-sulpho                                                                          ethanolamine                                       benzene sulphonic acid                                                                       benzoic acid                                            ______________________________________                                    

When dissolved in an aqueous ink medium and printed on to plain paperusing a thermal ink jet printing machine, the compounds of Examples 2-10gave results similar to those given by the product of Example 1.

We claim:
 1. A monoazo compound of the Formula (1) and salts thereof:##STR9## wherein: each of R¹ and R², independently, represents H,halogen, alkyl or acylamino;each of R³, R⁴ and R⁵, independently,represents H, C₁₋₆ -alkyl substituted by --OH or --SO₃, H, C₁₋₆-alkenyl, substituted C₁₋₆ -alkenyl, aryl or substituted aryl, otherthan groups comprising the residue --A--NR⁷ R⁸ wherein A represents anoptionally substituted alkylene group containing 2 or more carbon atomsand each of R⁷ and R⁸, independently, represents H or optionallysubstituted hydrocarbyl or R⁷ and R⁸ together with the attached nitrogenatom form a 5- or 6-membered ring; and R⁶ represents a group selectedfrom C₁₋₅ -alkyl, C₁₋₆ -alkenyl, substituted C₁₋₆ -alkenyl and arylsubstituted by one or more substituents selected from --OH, --COOH and--SO₃ H, other than groups comprising the residue --A--NR⁷ R⁸ wherein,A, R⁷ and R⁸ are as defined above; or R³ and R⁴ together with theattached nitrogen atom and/or R⁵ and R⁶ together with the attachednitrogen atom form a 5- or 6-membered ring other than a piperazine ring;the compounds of Formula (1) being free from fibre-reactive groups andany carboxyl substituents present in the compounds being attached in theform of one or more residue of the following formulae: ##STR10##
 2. Anink composition comprising a solution of a compound or salts thereofaccording to claim 1 in an aqueous medium.
 3. A process for printing asubstrate with an ink composition comprising forming the ink into smalldroplets by ejection from a reservoir through a small orifice so thatthe droplets are directed at a substrate wherein the ink compositioncomprises at least one compound or salt thereof according to claim 1 inan aqueous medium.
 4. A paper or an overhead projector slide or textilematerial printed with an ink composition wherein the ink compositioncomprises at least one compound or salt thereof according to claim
 1. 5.A process for the coloration of a textile material with an inkcomposition comprising a compound or salt thereof according to claim 1which comprises the steps:i) applying to the textile material by inkjetprinting the ink composition; and ii) heating the textile material at atemperature from 50° C. to 250° C. to fix the compound on the material.6. A textile material coloured with an ink composition according toclaim 2.